Please note a website outage is scheduled for Thursday 11 July from 6-8am. We apologise for any inconvenience.

Wai me taiao

Water & environment

We investigate water quality, identify contamination sources, and develop resources to better manage waterways, the surrounding environment, and potential risks to public health.

Water & environment block header


At ESR we understand the health of our water is critical to the health of our people. E ora ana te wai. Water is life.

We look at the relationship between drinking water, surface water, stormwater and wastewater, to understand how it affects, and is affected by, the health of our main water source, groundwater. 

We detect and monitor threats to our water, including the impact of climate change, while exploring sustainable solutions to protect vital water sources and manage waste products. Our focus is on improving te mauri o te wai so we can all trust the quality of the water we drink, play in and use every day. 

Find out more about our specialist and research areas in the links above, and our team and services below.

Specialist services

Specialist services

We provide health authorities, local and central government, industry and communities with scientific advice and expertise on the management of drinking water, groundwater, recreational water and wastewater. Please contact us to explore if our expertise can help your organisation.

Microbial Risk Assessment (MRA) tool


The Microbial Risk Assessment (MRA) tool provides an objective and transparent basis for consent decision-making on land use applications and their impact on drinking water supplies.

Protecting our drinking water from potential microbial contamination is critical for regional councils. An effective approach to assessing the risks posed by land use activities in close proximity to protected drinking water zones is needed in order to make informed consent decisions. ESR scientists are working alongside GNS and Environment Canterbury on a new model for microbial risk assessment of land use on drinking water supplies.

Groundwater modellers, hydrologists and microbiologists at ESR and GNS, along with Environment Canterbury (ECan), developed the Microbial Risk Assessment (MRA) tool to provide a more objective and transparent basis for consent decision-making on land use applications. This risk assessment tool involves modelling potential microbial contamination of groundwater supplies from land use activities such as community and on-site wastewater management systems, pastoral farming, wildfowl, stormwater systems, and animal effluent/manure application within ‘source protection zones’ – areas of protection around drinking water sources. 

The MRA tool includes a range of soil and groundwater system types found throughout Aotearoa New Zealand, modelling various permeabilities, topographies, recharge rates, hydraulic gradients, and lithologies. The tool also includes four climate types for modelling, representing relevant regions of the country. 

This MRA tool offers two significant improvements over the existing guidelines: improved inputs and improved risk modelling. It considers more input types, including additional land-use activities, multiple on-site wastewater management systems, and supply wells that are pumped at different rates. This improves the usefulness and application of the model as well as the risk model accuracy. In addition, the MRA also provides additional information and visualisation of uncertainty to assist in understanding trade-offs in risk with different separation distances and land use activities. Instead of evaluating at only a 95% confidence level, the entire spectrum of risks can be considered, from very risk averse setting at 99%, to more risk tolerant applications.

Benefits to land users and regional councils

The MRA benefits both land users and regional councils by providing greater guidance and certainty to stakeholders, reducing variation in assessment quality, assisting in consent processing, and avoiding duplication of effort in developing methods by individual regional councils.

The team is now building a user interface that will allow easy access and adoption of the MRA, assisting planners throughout Aotearoa New Zealand – and potentially beyond.

Get in touch

For questions about the tool, how to use it and what the benefits are; or to collaborate, share knowledge or develop partnerships projects in the groundwater or water quality space, get in touch with the Groundwater team. 

Water Quality

Waterborne outbreak investigations

ESR's water scientists can identify a range of waterborne pathogens within a water sample and can link the bacteria to those found in another source such as cattle, sheep or poultry. Using sequencing facilities on-site we can determine the complete picture of microbes present in a water sample and the impact of activities, such as discharges, on the health of the microbial community present.

Tracking faecal sources

When waterways become contaminated with faeces, identifying the source of the pollution is an important part of the contamination management strategy. ESR has a range of molecular and chemical techniques that help to identify sources of faecal contamination of water, whether they are from farms, domestic or feral animals, humans or birds. For example, if an initial test indicates high levels of E. coli, we undertake one or more assays from our ‘toolbox’ of methods. We then develop a strategy for determining the most  efficient way to identify the likely faecal contamination source, which includes a ‘decision tree’ outlining the steps to obtaining the most relevant information for the least financial outlay. We have an excellent record of helping local government staff with water management responsibilities to manage and reduce water pollution levels.

Surface water assessments

Our experts can assess the quality of surface and recreational waters and determine the cause of water pollution, including differentiating between sources of pollution. Our work includes developing monitoring and reporting programmes, applying bacterial and viral tracers to mark and follow effluent plumes, and conducting microbial risk assessments on discharges.

Drinking water standards and safety


We advise clients on the quality of their drinking water, report to the Ministry of Health on compliance with drinking water standards, assist with the management of large water quality datasets, and help develop resources to address public health risks associated with water supplies.

Register of recognised laboratories for New Zealand

To demonstrate compliance with the New Zealand Drinking-Water Standards, water suppliers need to monitor the quality of their drinking water by taking water samples and having them analysed. The Ministry of Health requires all such testing to be performed by laboratories that have appropriate skills and quality assurance procedures and to be registered.

The Register of Recognised Laboratories for New Zealand is prepared annually by ESR for the Ministry of Health and provides easily accessible information about the laboratories that have been assessed by IANZ and found to comply with either ISO 17025 or the Ministry of Health Level 2 Criteria analytical laboratories.

The register includes information such as the name of the laboratory, its contact details, and certified methods for determinants the laboratory can test for.

Drinking water supply and quality

With backgrounds in public health, microbiology, environmental radioactivity and chemistry, our scientists help clients to understand the quality of their drinking water and the implications of that quality for water treatment.

Our clients benefit from our direct involvement in preparing New Zealand’s drinking-water standards. Our responsibility to provide the Ministry of Health with annual reports of compliance with those standards, means we can advise clients on interpreting the standards and the next steps required for compliance, as well as help develop resources to address public health risks associated with water supplies.

In addition, we help those clients with major water-related responsibilities to manage large water-supply and water-quality datasets. With more than a decade’s experience in summarising and reporting on such datasets, we can help clients make sense and benefit from the data.

Testing & Analysis

Testing & analysis services

We detect and identify a range of waterborne pathogens as well as identifying their source and contaminant pathways.

Learn more

Experts in the area